The short term effectiveness of islet transplantation for alleviating hypoglycemia and controlling glucose homeostasis while limiting or even avoiding the nedd for exogenous insulin has been established despite protocol modifications in donor selection, islet preparation or recipient treatment, insulin independence with adequate metabolic control was however rarely prolonged beyond two years. The most frequently proposed explanations include chronic allogenic rejection, recurrence of autoimmunity and beta cell toxicity from administered immunosuppressive drugs.